The information in this document is based on these software and
hardware versions:

All Cisco routers

All Cisco IOS® software versions

Note: This document does not apply to Cisco Catalyst switches or MGX
platforms, but only to Cisco routers.

The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.

Cisco processors have timers that guard against certain types of system
hangs. The CPU periodically resets a watchdog timer. The watchdog timer
basically controls the time of each process. If the timer is not reset, a trap
occurs. If a process is longer than it must be, the watchdog timer is used to
escape from this process.

This only occurs if something goes wrong. Based on the situation, the
router can reset itself, or recover from the failure and generate an error
message in the console logs, which looks like this:

If you have the output of a show version
command from your Cisco device, you can use to display potential issues and fixes. To use , you must be a
registered
customer, be logged in, and have JavaScript enabled.

You can use Output Interpreter to display potential issues
and fixes. To use Output Interpreter, you must be a
registered
customer, be logged in, and have JavaScript enabled.

The root cause of the watchdog timeout can be hardware- or
software-related. Here are the common symptoms through which you can identify
the source of the problem:

If a router that has been properly operational for months suddenly
starts to reload every 20 minutes, or if it continuously reboots and you can no
longer access it, the problem is most likely a hardware-related issue. This is
also the case if a new module has been installed recently, and the router
crashes by watchdog timeout afterwards.

If the router starts to crash after a configuration change or a
change in the Cisco IOS software version, it is probably a software-related
issue.

The first step to troubleshoot this type of issue is to identify the
type of watchdog timeout that you encounter. There are two types of Watchdog
Timeouts:

Most of the time, these messages indicate a hardware issue, either with
the main processor board or with one of the modules.

After you identify a software watchdog timeout, the next step is to
check the Product Field Notice
Summary for your platform and all the components installed in that
system for known critical hardware issues. For example, there is one Field
Notice for the Cisco 3600 Series Router:
Cisco
3600 T1/E1 PRI Module Watchdog Timeouts. Ensure that you check the Field
Notices before you troubleshoot further.

If a new module has been recently installed, you must first try to
remove it to verify whether it is the reason for the watchdog timeout. If the
watchdog timeout persists, try to re-seat all removable components.

If the watchdog timeout continues at this point, there are no Field
Notices for your hardware, and if no new module has been recently installed, go
ahead and replace the main processor board. On high-end platforms, the
processor board is a separate card (such as the NPE-400 or RSP8). On low-end
platforms (Cisco 1700, 2500, 4000, 2600, 3600, and so on), the motherboard
cannot be shipped separately. In this case, you have to replace the chassis
itself.

If you have the output of a show
stacks command from your Cisco device, you can use to display potential issues and fixes. To use , you must be a
registered
customer, be logged in, and have JavaScript enabled.

However, the system was stuck in a loop before the reload. Therefore,
the stack trace need not necessarily be relevant. You can upgrade to the latest
Cisco IOS software version in your release train to eliminate all known Process
Watchdog issues. If a crash still occurs after the upgrade, collect as much
information as possible (see
Troubleshooting
Router Crashes), and contact your technical support representative.

There are other console error messages related to watchdog timers. Do
not confuse these messages with a watchdog timer crash. Be sure to check the
meaning of these error messages with the help of the
Error
Message Decoder
(registered customers only)
. This tool gives you a detailed explanation of many
error messages, and recommends actions to resolve them.

This message indicates that the specified process has run for too long,
and the processor has not been relinquished. The system has shut down the
indicated process. Based on your configuration, this can lead to a system
crash. If the message occurs only once, you need not take any action. However,
if it occurs again, you must treat it as a Process Watchdog Timeout, and take the
necessary action.

If you still need assistance after following the
troubleshooting steps above and want to
open
a service request
(registered customers only)
with the Cisco TAC, be sure to include the following
information:

Troubleshooting performed before opening the service request.

show technical-support output (in
enable mode if possible).

show log output or console
captures, if available.

execute-on slot [slot #]
show tech for the slot which experienced the line card
crash.

The
crashinfo
file (if it is available, and has not already been included in the
show technical-support output).

Please attach the collected data to your service request in
non-zipped, plain text format (.txt). You can attach information to your
service request by uploading it using the
TAC Service Request tool
(registered customers only)
. If you cannot access the Service Request tool, you can send the
information in an email attachment to attach@cisco.com with your service request
number in the subject line of your message.

Note: Please do not manually reload or power-cycle the router
before collecting the above information unless required to troubleshoot a line
card crash on the Cisco 12000 Series Internet Router, as this can cause
important information to be lost that is needed for determining the root cause
of the problem.